'This approach is based on accelerating and slowing down the front and rear parts, respectively, of the probe beam to create a well-controlled temporal gap,' scientists write.
July 14, 2011 (World News Trust) -- Scientists have uncovered a remarkable ability to manipulate and control electromagnetic fields to produce effects such as perfect imaging and spatial cloaking.
"To achieve spatial cloaking, the index of refraction is manipulated to flow light from a probe around an object in such a way that a 'hole' in space is created, and it remains hidden," scientists report in the paper "Demonstration of temporal cloaking."
"Alternatively, it may be desirable to cloak the occurrence of an event over a finite time period, and the idea of temporal cloaking was proposed in which the dispersion of the material is manipulated in time to produce a 'time hole' in the probe beam to hide the occurrence of the event from the observer," write Moti Fridman, Alessandro Farsi, Yoshitomo Okawachi and Alexander L. Gaeta from the Cornell University School of Applied and Engineering Physics.
"This approach is based on accelerating and slowing down the front and rear parts, respectively, of the probe beam to create a well-controlled temporal gap in which the event occurs so the probe beam is not modied in any way by the event," they write.
"The probe beam is then restored to its original form by the reverse manipulation of the dispersion. Here we present an experimental demonstration of temporal cloaking by applying concepts from the time-space duality between diffraction and dispersive broadening.
"We characterize the performance of our temporal cloak by detecting the spectral modication of a probe beam due to an optical interaction while the cloak is turned off and on and show that the event is observed when the cloak is turned off but becomes undetectable when the cloak is turned on.
"These results are a signicant step toward the development of full spatio-temporal cloaking," they report.